Performance Gain Stock Rockers to 1.5RR?

[Dave Gantz]

Originally Posted by Dan Fahey

I have been looking everywhere, including old Dyno Books.
Found a video testing Stamped Rocker vs RR Dyno Test on a Jeep engine. They did a lot of interesting upgrades and used Harland Rockers 1.7 Rockers.

After running a series of head and header tests. They ran a test with the Stock Rockers. RR's showed a measurable improvement. The Video did not say what the Stamped Rocker Ratio was. This needs to be answered. If roughly the same the RR's was a nice improvement.



Our LT1 Stock Engines in our Impalas and Camaros it popular to add a 1.6 RT or RR's replacing stock rockers measured at 1.47.

Dyno testing with Bryan Herter showed measured 15hp rear wheel improvement. Got another 5-7 with an upgraded tune for total of 22hp.
Dan

Stock Eliminator, in theory, is the antithesis of the internet. People have worked for 30, 40 or more years to find out what they know about what makes their combo get to the end of the track before you. Now, you want them to tell you what they learned?
The internet can seem to be about "tell me what you have worked hard to learn. Oh, and, thanks." But responses can be cryptic. And I would expect them to be. Just like in the "prehistoric" days. You have to take what you're told and make the best of it.

[Billy Nees]

Dan, on my 307 (definitely not an LT-1!) going from the stamped rockers to roller rockers was worth absolutely nothing.

[Mark Yacavone]

Originally Posted by Billy Nees

Dan, on my 307 (definitely not an LT-1!) going from the stamped rockers to roller rockers was worth absolutely nothing.

I have seen this right on the dyno too. Another "it depends".

[SSDiv6]

Originally Posted by Mark Yacavone

I have seen this right on the dyno too. Another "it depends".

Mark is correct. It depends on the engine, especially on the type of engine, horsepower output and RPM. A higher horsepower/high RPM engine will benefit from aftermarket rocker arms due to reduced rocker arm deflection and stabilization of the valvetrain. Since the liberalization of camshaft specifications with more radical lobes and high pressure valve springs, a stamped rocker arm will have a very limited life.

[Billy Nees]

Originally Posted by SSDiv6

A higher horsepower/high RPM engine will benefit from aftermarket rocker arms due to reduced rocker arm deflection and stabilization of the valvetrain. Since the liberalization of camshaft specifications with more radical lobes and high pressure valve springs, a stamped rocker arm will have a very limited life.

And since we're on the subject, the"aftermarket rocker arms" that "reduced rocker arm deflection" and allowed the "stabilization of the valvetrain" ALSO made it a necessity to port your heads and intake if you wanted to stay competitive. In other words, in the good old days, you could either run well and keep your stuff together for a 7 round race or go fast and gamble on when you were gonna break a rocker.

[GUMP]

I ran treated and coated stock rockers that we machined to work with a 7/16 stud on my LT1's. I saw no performance gain going to a roller rocker. Limited travel lifters was a different story.....

[Larry Hill]

The truck engine liked the 7/16 studs they had less deflection than the 3/8.